Ditching machine



Oct. 15, 1940.

E. L. TUNSEN El AL DITCHING MACHINE 2 Sheets-Sheet 1 Filed Feb. 27, 1939INVENTORS m m W I T S Patented Oct. 15, 1940 2,218,222 DITCHING MACHINEElmer L. Tunsen and Clarence A. Rasmussen, Modesto, Califi; said Tunsenassignor to said Rasmussen Application February 27, 1939, Serial N0.258,643

- 6 Claims.

This invention relates to ditching machines and particularly to oneintended for use in digging a ditch the lower portion of which serves asthe form for the bottom half of a concrete pipe, which is formed bypouring the concrete directly into the ditch.

Such a pipe is intended to be round, and one object of our invention isto provide a digger which will form the lower half of the ditch to atrue semicircular shape. 7

In' laying such a poured pipe line, it is requisite that the bore of thepipe shall be maintained at a certain dimension and that the thicknessof the pipe shall also be maintained at a certain definite dimension.

Another object of our invention therefore is to provide a digger for thepurpose which will maintain the desired accuracy as to width, depth andthe circular bottom form of the ditch at all times, and without anychecking up ever being necessary. It is also an object to provide forthe continuous removal of the dirt as it is dug or excavated, and thedepositing of such dirt well to one side of the machine and ditch.

Also, the digger is rapid in operation, and will work effectively in anytype of soil.

A further object of the invention is to produce a simple and inexpensivedevice and yet one which will be exceedingly effective for the purposefor which it is designed.

Thes objects We accomplish by means of such structure and relativearrangement of parts as will fully appear by a perusal of the followingspecification and claims.

In the drawings similar characters of reference indicate correspondingparts in the several views:

Figure 1 is a side elevation of our improved ditch digger shown as inoperation in a ditch and as mounted in connection with a drivingmechanism and a supporting vehicle.

Figure 2 is an enlarged transverse section of the digger on line 22 ofFig. 1.

Figure 3 is a sectional plane on line 33 of Fig. 2, but showing theopposed digger arms in tial features of our invention comprise a rigid,

relatively short shaped shield or casing 1 whose width is that of theditch 2 to be dug, and

whose lower portion is truly semicircular. The,

upstanding sides of the casing, above the axis of the curved portion,are vertical and parallel and are of a height to extend above the ,top

of the ditch, which is substantially as deep as it is wide, as plainlyindicated in Fig. 2.

The front of the casing is entirely open, while the back is closed by aplate 3. Projecting through this plate from behind and journaled in afixed bearing 4 is a driven shaft 5, disposed coaxial with the curvatureof the casing. This shaft extends to adjacent the front of the casing,and is there provided with a plurality of radial arms 5, preferably fourin number.

Fixed on the opposed ones of said arms adjacent their outer end arereversible cutting or scraping blades 1, disposed fiat on said arms sothat their width is radial with the shaft. The

blades are set at an outward angle to the axis of the shaftin such aposition that the outermost end of their cutting edge lies ahead of andoutwardlyof the inner periphery of the casing, or so as to excavate thedirt through a circular path whose outer periphery at the bottom,substantially conforms to the outer peripheral line of the casing,

Also fixed on all said arms radially inward of the cutters l are othernon-angularly disposed reversible blades 8, adapted at their forward endto engage the vertical face of the dirt at the head of the ditch andexcavate the dirt in circular paths with a scraping action. 1 Eachcutter is relatively narrow, so as to cut a corresponding narrowcircular swath, but all the cutters are arranged in such relativelystaggered relation on the various arms that the face of dirt will beexcavated in the form of a number of such narrow swaths, as indicated bythe various circular lines H1 in Fig. 2, and without a radial break fromthe outermost cutters l to adjacent. the central shaft. If desired, thehub of the arms may be provided with a central cutter as indicated at 9.I

The circular path of cutting of the outer ,cuttersB will practicallyreach ground level at the top and center, leaving of coursesubstantially triangular masses of dirt on each side at the top anduntouched by the cutters, as indicated at I l. However, as will beobvious, the straight sides of the casing, with the forward movement ofthe latter, shear through these triangular portions of dirt at the sidesthereof, and due to their unsupported overhang, they then drop off ofthemselves.

The casing, besides serving to shear and true the walls of the ditch,also serves as a receptacle for the excavated dirt, preventing the samefrom falling into the finished ditch, and thus keeping the ditchperfectly clean. I

.the side of the casing toward which the paddles are turning and intothe bottom of, a housing l3 mounted as a unit with the casing just aboveground level. A rotary paddle unit I4 is turnably mounted on thishousing on a horizontal axis, and engages the dirt as it is thrownupwardly by the paddles l2 and delivers such dirt onto an endlessconveyor 1 5 of conventional form. This conveyor is also mounted as aunit with the casing and housing and extends laterally a suitabledistance, so as to discharge onto the ground well clear of the ditch. 1

The shaft 5, paddle unit and conveyor are. all driven at a relativelyhigh speed. By reason of this, the dirt is practically pulverized as itis excavated andit is thrown up by paddles l2 with sufficient velocityto cause it to enter housing l3 and be acted on by paddle unit It.

In operation, besides the various shafts being driven in the properdirection, the digger as a whole must be moved along the ground, whilemaintaining shaft 5 as near to parallelism with the ground surface as ispossible. In connection with the supporting of the digger necessary toobtain the above results, it may also be desirable to set the digger atvarious adjustable levels.

The support and adjustment of the digger may be accomplished in variousways, that shown here being illustrative. In this showing, the casingabove ground is vertically slidable between the side beams N5 of achassis frame, which is supported from the ground outwardly of the beamsby endless track units ll of conventional form and which may or may notbe self-propelled.

The digger casing is mounted in connection with the frame for verticaladjustment and so as to maintain the shaft 5 parallel to the groundlevel at all times by means of parallel and vertically spacedcompression arms I8 pivoted in connection with the casing at the backand extending rearwardly to pivotal connection with a depending framemember l9. An upstanding rack bar 20 is pivoted on each upper arml8,"and is engaged by a pinion 2| mounted in connection with anirreversible worm control device 22.

It will therefore be seen that by vertical movement of the rack bars,the digger structure, together with the adjacent end of the conveyor l5,will be vertically adjusted. In order to relieve the digger of some ofthe weight of the conveyor without affecting the unitary association ofthe conveyor with housing l3 regardless of the level of the latter, thelower end of said conveyor may be pivotally mounted in connection withthe housing and supported toward its outer end for movement laterally ofthe digger on a lateral arm unit 23 mounted rigid with the chassis frameas shown in Fig. 2.

The chassis carries a suitable power plant such as a gas engineindicated at 24. A drive connection 25 extends between the engine andthe pivot point of the lower arm l8 with member l9, and another driveconnection 26 extends between the lower end of connection 25 and therear end of shaft 5 at the forward pivot point of said lower arm l8.Auxiliary drives 21 of suitable type connect shaft 5, behind the casing,with the rotary paddle unit I 4 and conveyor l5 so that all rotatingparts move at predetermined synchronized speeds.

By means of a supporting and drive mechanism such as that abovedescribed, the chassis may be propelled or pulled ahead whilemaintaining the digger unit in the desired upstanding position at alltimes, and all the rotating members of the digger will be driven withoutinterference regardless of the vertical setting of the digger.

From the foregoing description it will be readily seen that We haveproduced such a device as substantially fulfills the objects of theinvention as set forth herein.

While this specification sets forth in detail the present and preferredconstruction of the device, still in practice such deviations from suchdetail may be resorted to as do not form a departure from the spirit ofthe invention, as defined by the appended claims.

Having thus described our invention, what we claim as new and useful anddesire to secure by Letters Patent is:

1. A ditch digger including a rotary excavating unit having its axishorizontal and adapted to extend lengthwise of a ditch for engagementwith the head wall thereof and excavate a circular area, means tosupport the unit for movement 1- along the ground and so that its centeris below ground level and means provided with the unit to cut throughthe head-wall dirt above the horizontal central plane of said area andtangent to the periphery thereof to the level of the top of saidcircular area and on both sides thereof.

2. A ditch digger comprising a rotary excavator adapted to excavate acircular area, means to mount the excavator for movement along theground with its axis horizontal and so that it will operate on the headwall of the ditch, a casing mounted in connection with the rotaryexcavator behind and with its front edge adjacent the dirt engagingelements thereof; said casing including a lower-portion concentric withthe shaft and substantially the same diameter as that of the excavatorand vertical sides upstanding from and tangent to said lower portion.

3. A ditch digger comprising a rotary excavator adapted to excavate acircular area, means to mount the excavator for movement along theground with its axis horizontal and so that it will operate on the headwall of the ditch, a casing mounted as a unit with and open to theexcavator in position to receive the dirt as excavated, means to engagesuch dirt and throw the same upwardly, a conveyor extending laterallyfrom the digger above ground level and means to engage such upwardlythrown dirt and deliver the same onto the conveyor.

4. A ditch digger comprising a rotary excavator adapted to excavate acircular area, means to mount the excavator for movement along theground with its axis horizontal and so that it will operate on the headwallof the ditch, a casing mounted as a unit with and open to theexcavator in position to receive the dirt as excavated and extendingrearwardly from the excavator, the back of the casing being closed andits lower portion being circular and concentric with the excavator,paddles disposed radially in said circular portion of the casing andmounted for rotation with the excavator so as to throw the dirt up zoneside of the casing from the bottom thereof, a housing in the casing onsaid side above and clear of the path of rotation of the paddles, saidhousing having a bottom opening through which said upwardly thrown dirtpasses, a conveyor leading laterally from the housing and a rotarypaddle unit in the housing to engage the dirt thrown into the same frombelow and deliver such dirt onto the conveyor.

5. A ditch digger comprising a vertically disposed U-shaped casing thelower portion of which is semicircular, means supporting the casing formovement along the ground so that said lower portion is below groundlevel with its axis parallel to the ground surface and a rotaryexcavator mounted as a unit with the casing at the front end anddisposed concentric with the lower (portion thereof; said excavatorincluding cutting elements extending radially out to engage the 'dirtahead of but adjacent the casing and ex- 'cavate the dirt along acircular path whose outer diameter is substantially the same as theouter diameter of the lower portion of the casing.

' 6. A ditch digger comprising a rotary excavator to engage the headwall of the ditch being dug, a casing mounted as a unit with and; behindthe excavator to receive the dirt asexcavated, a

housing in the casing above the excavator and open to the casing, meansin the casing to engage Ithe dirt in the casing and deliver the sameinto the housing, and additional means to engage the dirt as deliveredinto the housing and remove isuch dirt and deposit the same on theground to one side of the digger.

ELMER L. TUNSEN. CLARENCE A. RASMUSSEN.

